Speed Distance Time Calculator
Solve for speed, distance, or time using the formula d = s × t. Supports all major units including mph, km/h, m/s, and more.
| Variable | Value |
|---|
Speed Distance Time Formulas
The speed distance time relationship is expressed in three equivalent formulas, each solving for a different unknown variable.
| Solve For | Formula | Example |
|---|---|---|
| Speed | s = d / t | 100 mi / 2 hr = 50 mph |
| Distance | d = s × t | 60 mph × 3 hr = 180 mi |
| Time | t = d / s | 200 mi / 50 mph = 4 hr |
Common Speed Unit Reference
Speed units in the reference table below are converted relative to meters per second (m/s), the SI standard.
| Unit | Symbol | Meters per Second |
|---|---|---|
| Miles per hour | mph | 0.44704 |
| Kilometers per hour | km/h | 0.27778 |
| Meters per second | m/s | 1 |
| Feet per second | ft/s | 0.3048 |
| Knots | kn | 0.51444 |
| Speed of light | c | 299,792,458 |
How Speed, Distance and Time Relate
Speed, distance, and time are the three cornerstones of motion mathematics. Any one of them can be found when the other two are known, making this the most fundamental calculation in physics, navigation, and everyday travel planning.
Speed vs Velocity
Speed and velocity are often used interchangeably but are technically different. Speed is a scalar quantity (magnitude only), while velocity is a vector quantity (magnitude plus direction). If you drive 60 mph north, your speed is 60 mph and your velocity is 60 mph north.
Average Speed vs Instantaneous Speed
Average speed is total distance divided by total time for an entire trip. Instantaneous speed is how fast you are moving at any specific moment. A car’s speedometer shows instantaneous speed, while the formula d = s × t uses average speed.
Frequently Asked Questions
Speed equals distance divided by time: s = d / t. For example, if you travel 100 miles in 2 hours, your speed is 100 / 2 = 50 mph.
Distance equals speed multiplied by time: d = s × t. For example, traveling at 60 mph for 3 hours covers 60 × 3 = 180 miles.
Time equals distance divided by speed: t = d / s. For example, at 50 mph to cover 200 miles takes 200 / 50 = 4 hours.
Speed is the rate of change in position without regard to direction. Velocity is speed with a specific direction. If you walk at 2 m/s forward or backward, your speed is 2 m/s in both cases, but your velocity differs by sign.
60 miles per hour is approximately 96.56 kilometers per hour. The conversion factor is 1 mph = 1.60934 km/h, so 60 × 1.60934 = 96.56 km/h.